No, I don't think it will kill Crashing Storm. See, that tier is supposed to offer different AOE attacks. Right now, we pretty much have to pick Crashing Storms, but Fury of Air actually does the same amount of damage on their own, with FoA costing slightly more MS, but it's on all the time and doesn't need to be cast, freeing up GCDs for something else. The slow is kinda nice as well, so there is some utility as a trade for the higher MS cost.
Sundering would be for PvP or if you need a costly stun.
Alright okay, clearly FOA does not trigger Gathering Storms, but maybe all three talents on that tier should - or at least FOA in some fashion. And FOA can't proc Stormbringer either, but then again, I still think it's weird that CL can do that.
If you took FOA, you would have that + the occasional CL to cleave, and then there's your AOE. Or just take Crashing Storms for a simple rotation.
This would make the entire tier a proper AOE tier. Sure, FoAs cost could probably be changed to 4 MS/s, but eventually our MS generation is probably going to be high enough so that this doesn't matter.